Reclosable lid for a vacuum food container and having a vacuum release button

ABSTRACT

A sheet metal lid has a rim portion with a resilient sealant for releasably coupling the lid to a glass or metal container enclosing a vacuum food product. The lid has a center vacuum release vent button with a top wall having a thinner top edge portion forming a laterally outwardly projecting arcuate lip portion. The arcuate lip portion overlies an arcuate score line at the bottom of the button and formed within the inner surface of the lid. A sealant material is bonded to the inner surface of the button and has an outer flange portion overlying the score line. The vent button pops upwardly above the rim after the vacuum is released, and the flange portion resents to cover the score line and protect the food product. A dimple is formed in the top edge portion to indicate where to press for releasing the vacuum.

BACKGROUND OF THE INVENTION

This invention relates to a closure for a vacuum food container and of the type disclosed in applicant's U.S. Pat. No. 5,979,688 and No. 6,206,220. These patents are directed to a thin sheet metal closure or cap or lid for a vacuum packed and sealed food container wherein the closure is removably sealed to the container and reclosable on the container. Commonly, the container is formed of glass but may also be formed plastic or sheet metal, and the vacuum within the sealed container is released to facilitate or simplify the removal of the closure or lid from the container. Other forms of containers with reusable closures for vacuum food containers and having a vacuum release structure before the closure is removed from the container are disclosed in U.S. Pat. No. 3,410,436 and published U.S. patent application No. US 2014/0103044.

As used herein, the term container includes a glass or sheet metal or plastic container, and the term lid includes any form of closure such as a twist-on, twist-off sheet metal cap or a press-on, press-off sheet metal cap or lid for a container. The lid has a peripheral chime or rim portion with a bonded sealant material to form a releasable sealed coupling between the lid and the container. In such an enclosed vacuum food container and lid assembly, it has been found desirable to add an easily activated vacuum release button to the lid after the lid has been completely formed on tooling which shapes the lid and has the bonded sealant material on the inner surface of the rim portion of the lid. It is also desirable to minimize the thickness of the sheet metal, such as sheet steel or aluminum, which forms the lid and to provide a clearly visible tamper-proof indication when the vacuum has been released from the container.

SUMMARY OF THE INVENTION

The present invention is directed to an improved sheet metal lid for a container having a vacuum enclosed food product and which has a vacuum release button to facilitate removal of the lid, and to the tooling and method for producing lid. The tooling and method are especially adapted for adding the vacuum release button to a lid which has been pre-formed to be releasably attached and sealed to a glass jar or sheet metal container. In accordance with a preferred embodiment of the invention, a sheet metal lid having a peripheral rim portion with a bonded sealant material has a center portion formed with tooling to form an upwardly projecting and rounded dome-shaped thinner portion in a first stage of a progressive die. The dome-shaped portion is flattened in a second die stage to form an upwardly projecting and slightly sloping or tapered flat top button. In a third progressive die stage, the bottom portion of the button is formed with an upwardly projecting crescent or arcuate shape score line within the inner surface or product side of the sheet metal lid. The score line may be progressively deeper from the center of the arcuate score line to the opposite ends of the score line.

The top portion of the button is then deformed along an arcuate top edge portion of the button in another progressive die stage to thin the top edge portion and form a laterally outwardly projecting lip portion at the top of the button. At this stage, the thinner arcuate top portion of the button may be formed with an upwardly projecting dimple to help provide an indication where the button should be depressed with a person's finger to shear the sheet metal at the score line. A sealant material is then bonded to the inner surface of the button and includes a lip or flange portion which projects outwardly on the inner surface of the lid to cover the score line. When the edge portion of the vacuum release button is depressed or pressed downwardly, the flange portion of the sealant separates or peels away from the inner surface of the lid to release the vacuum within the container. When the button is released, the flange portion of the sealant recontacts the inner surface of the lid due to spring hinge action of the opposite side of the button. The outwardly projecting lip portion of the button prevents the finger depressing the button to engage the severed or sheared sheet metal edge of the lid at the score line and thereby protects the depressing finger that releases the vacuum within the container.

Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a sheet metal lid constructed in accordance with invention;

FIG. 2 is a vertical section of the lid shown in FIG. 1 and releasably attached and sealed to the top portion of a glass vacuum food container;

FIG. 3 is a vertical section of the lid shown in FIG. 1 before being attached or coupled to a container;

FIG. 4 is a vertical section of a conventional sheet metal lid before sealant material is bonded to the rim portion of the lid;

FIGS. 5-8 are enlarged vertical sections through the progressive die tooling for forming a vacuum release button within the conventional lid shown in FIG. 4;

FIG. 9 is an enlarged vertical section through the vacuum release button formed within the lid and showing the arcuate score line before sealant material is bonded to the inner surface of the button;

FIG. 10 is an enlarged vertical section through the vacuum release button after sealant material is bonded to the inner surface of the button and after the button is depressed to shear the score line and release vacuum within the container;

FIG. 11 is a vertical section similar to FIG. 2 and showing the vacuum release button projecting above the rim portion of the lid after vacuum has been released from the container;

FIG. 12 is an enlarged top view of the vacuum release button and showing with enlarged fragmentary sections of FIGS. 13-16 the progressive depth of the crescent or arcuate-shape score line formed within the inner surface of the lid, as shown in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a sheet metal lid 20 having a centerline 21 formed in accordance with the invention to include a peripheral chime or rim portion 22 which releasably engages or attaches to an upper portion 24 (FIG. 2) of a food container 25 in a conventional manner with a twist-on, twist-off coupling or a press-on and press-off coupling to the container. The inner surface of the rim portion 22 of the lid of the lid 20 includes a bonded resilient sealant material 28, such as a food grade PVC or plastisol, which forms a vacuum-tight seal with the container 25, in a conventional manner. A convention sheet metal lid 30 is shown in cross-section in FIG. 4 and is commonly produced of thin sheet metal or sheet steel having a thickness, for example, of about 0.007 inch. After the sealant material 28 is bonded to the rim portion of the lid 30, the lid is preferably transferred to a high speed mechanical press having progressive tooling or dies which form the lid 30 into the lid 20 in accordance with the invention.

Referring to the progressive tooling stages shown in FIGS. 5-8, a center portion of a conventional sheet steel lid 30 is formed upwardly in a first stage of the progressive tooling by die components 33 and 34 to form a dome-shaped center portion 35 having a reduced wall thickness at the top, for example, of about 0.006 inch. In the next progressive die stage of FIG. 6, die components 37 and 38 form the dome-shaped portion 35 into a flat wall top portion 42 and a circular side wall portion 43. In a following progressive die stage of FIG. 7, die component 46 and 48 form a crescent-shape or arcuate score line 50 within an inner surface or product side of the sheet metal adjacent the base or bottom portion of the flat top button portion 42,

Referring to FIGS. 12-16, the arcuate score line 50 is preferably formed so that it has its maximum depth within the inner surface of the sheet metal at the center of the arcuate score line, as shown in FIG. 16. The depth of the score line becomes progressively less towards opposite ends of the score line, as shown in FIGS. 14 & 15 until the score line terminates at FIG. 13 to provide the score line with an arcuate distance of about 240 degrees. For example, in sheet steel having a thickness of about 0.007 inch, the sheet steel 30 has a minimum thickness at 55 at the bottom of the score line 50 of about 0.0008 inch and located at the center of the arcuate score line shown in FIG. 16.

Referring to FIG. 8, die components 57 & 58 at progressive die stage form the flat top button 42 into a slightly inclined or sloping top wall portion 60 and a thinner edge portion 62 of about 0.004 inch and a laterally outwardly projecting arcuate lip portion 65. The lip portion 65 overlies the arcuate score line 50 by about 90 degrees, and dies 57 & 58 also form a part cylindrical or arcuate vertical wall portion 67 all of which cooperate to form vacuum release button 70. As shown in FIG. 9, the tooling components 57 & 58 may include an upward projection and a recess, respectively, to form an upwardly projecting dimple 72 within the top edge portion 62 of the button 70. As mentioned above and shown in FIG. 12, the arcuate lip portion 65 preferably extends peripherally by an arcuate distance less that the arcuate length of the score line 50, for example, with the lip portion 65 extending about 90 degrees and the score line 50 extends about 240 degrees.

Referring to FIGS. 2, 3, & 10, the vacuum release button 70 is provided with a resilient sealant material 80 such as the material 28 and which is bonded to the inner surface of the button 70. The material 80 includes an outwardly projecting peripheral flange portion 82 which covers and seals the score line 50 and protects the score line from being exposed to the food product within the container 25 and thereby protects the food product from being exposed to the sheet metal or sheet steel which forms the score line.

After the sheet metal lid 70 is attached or coupled to a container 25 and a vacuum has developed above the food product within the container, the top surface of the vacuum release button 70 is substantially flush with the top surface of the chime or rim portion 22 of the lid, as shown in FIG. 2. When it is desired to release the vacuum to facilitate the removal of the lid from the container 25, the thinner edge portion 62 of the button is depressed slightly downwardly by a finger to shear or sever the sheet metal lid at the score line 50 and thereby release the vacuum, as shown in FIGS. 10 & 11. When the button 70 and vacuum are released, the button 70 pops upwardly by the spring hinge action in the wall portion 43 opposite the score line 50, and the lid 20 returns to it's normal position as shown in FIG. 3. In this position, the top surface of the button 70 is above the top surface of the rim portion 22 to provide a clear indication that the vacuum has been released from the container. When the button 70 returns to its original position, as shown in FIG. 3, the flange portion 82 of the sealant material 80 recontacts or engages the inner surface of the lid, as shown in FIG, 3 and thereby enables the food product within the container to remain fresh and prevents the food product from being exposed to the edge surface of the sheet metal forming the score line 50,

While the lid 20 and the tooling and method for forming the lid herein described constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to the precise lid and method and tooling described, and that changes made therein without departing from the scope and spirit of the invention as defined in the appended claims. 

What is claimed is:
 1. A thin sheet metal lid having a peripheral rim portion with a bonded sealant material and adapted to be releasably secured to a container receiving a vacuum enclosed food product, the lid comprising a portion of the sheet metal lid projecting upwardly and forming a vent button having a sheet metal thickness less than the sheet metal thickness of a lid portion extending around the button, the lid having an arcuate score line extending partially into the sheet metal lid adjacent a bottom portion of the button, a top edge portion of the button projecting laterally outwardly and forming an arcuate lip portion overlying the score line, a top portion of the button sloping upwardly to the top edge portion of the button, a resilient sealant material bonded to an inner surface of the button and having a flange portion of the sealant material projecting laterally outwardly onto an inner surface of the lid and overlapping the score line, and the projecting flange portion of the sealant material effective to separate from the inner surface of the lid in response to depressing the top edge portion of the button for releasing vacuum from the container.
 2. (canceled)
 3. (canceled)
 4. A lid as defined in claim 1 wherein the inner surface of the vent button is filled with the sealant material on the lid having sealant material pre-bonded to the rim portion of the lid.
 5. (canceled)
 6. A lid as defined in claim 1 wherein the top edge portion of the button has an upwardly projecting dimple to indicate where the button should be depressed to release the vacuum.
 7. (canceled)
 8. (canceled)
 9. (canceled)
 10. A lid as defined in claim 21 wherein the arcuate score line extends into the sheet metal lid with a depth of the score line progressively reducing from under a center portion of the arcuate lip portion to opposite ends of the lip portion.
 11. A lid as defined in claim 21 wherein the top edge portion of the button has an upwardly projecting dimple to indicate where the button should be depressed to release the vacuum.
 12. (canceled)
 13. A method of adding a vacuum release button to a thin sheet metal lid having a peripheral rim portion with a bonded sealant material with the lid adapted to be releasably secured to the end portion of a container receiving a vacuum enclosed food product, the method comprising the steps of pressing a portion of the lid to form an upwardly projecting vent button having a sheet metal thickness less than the sheet metal thickness of a lid portion extending around the button, pressing an arcuate score line partially into the sheet metal lid adjacent a bottom portion of the button, and pressing a top edge portion of the button to form an arcuate lip portion projecting laterally outwardly over the score line from the top edge portion of the button.
 14. (canceled)
 15. A method as defined in claim 13 wherein the arcuate score line is pressed into the sheet metal lid with a depth of the score line progressively reducing from under a center portion of the arcuate lip portion to opposite ends of the lip portion.
 16. A method as defined in claim 13 wherein a sealant material is bonded to the inner surface of the vent button after the sealant material is bonded to the rim portion of the lid.
 17. A method as defined in claim 13 wherein the vent button is formed with a top wall portion sloping upwardly to the top edge portion of the button.
 18. A method as defined in claim 13 wherein the step of deforming a portion of the lid to form the vent button comprises forming a rounded dome-shape center portion of the lid.
 19. A method as defined in claim 13 and including the step of forming an upwardly projecting dimple within the top edge portion of the button to indicate where depressing the button releases the vacuum.
 20. (canceled)
 21. A thin sheet metal lid having a peripheral rim portion with a bonded sealant material and adapted to be releasably secured to a container receiving a vacuum enclosed food product, the lid comprising a portion of the sheet metal lid projecting upwardly and forming a vent button having a sheet metal thickness less than the sheet metal thickness of a lid portion extending around the button, the lid having an arcuate score line extending partially into the sheet metal lid adjacent a bottom portion of the button, and the button having a top wall portion sloping upwardly to a top edge portion projecting laterally outwardly and forming an arcuate lip portion overlying the score line.
 22. A lid as defined in claim 21 wherein the top edge portion of the button has a sheet metal thickness less than the sheet metal thickness of the adjacent top portion of the button. 